http://abcnews.go.com/Health/MindMoodNe ... d=12152238
Chronic pot smokers beware. A new study found that regularly smoking marijuana may lower cognitive function, especially if the person starts smoking before 16 years of age.
Experts split on whether marijuana works miracles or just hides symptoms.Study authors from Harvard-affiliated McLean Hospital wanted to examine the effects of chronic marijuana use on brain function.
In a paper presented today at the annual meeting of the Society for Neuroscience in San Diego, Dr. Staci Gruber, lead author of the small study, reported that study participants who began smoking pot before 16 years of age performed significantly worse on cognitive function tests than both non-smokers and those who became chronic smokers later in life.
Researchers defined chronic marijuana use as smoking pot at least five of the last seven days and a minimum of 3,000 joints in a lifetime. The average age of study participants was 22 years old. The data showed that chronic pot smokers repeated errors more often than the two other groups, even after the authors corrected them. They also had more trouble maintaining a set of rules, suggesting an inability to maintain focus...
...."We have to be clear about getting the message out that marijuana isn't really a benign substance," she said in a statement. "It has a direct effect on executive function. The earlier you begin using it, and the more you use of it, the more significant that effect."
Gruber also said it is unclear whether occasional marijuana use would have the same effect on cognitive function.
"It's impossible to tell whether our results would be the same in moderate smokers," said Gruber. "But there are even more of those people out there, so that will be the next place we go for our research."
